Deposition of thin films on a substrate surface is an important process in a variety of industries, including semiconductor processing, diffusion barrier coatings, dielectrics for magnetic read/write heads, and random access memory. Metal oxide films incorporating transition metals are used in semiconductor applications including high K gate dielectric films, active materials for ferroelectric memories, thin film battery cathodes, materials in silicon based light emitting devices and memory cells. Many metal-oxygen condensed phase systems employ metal oxides that are known to be stable at different oxidation potentials and have well-defined stoichiometric phases. For these materials it is generally possible to consistently obtain a desired metal oxide once an oxidation potential threshold is exceeded, and equilibrium is reached.
Methods for deposition of thin films include chemical vapor deposition (CVD) and atomic layer deposition (ALD). CVD processes involve exposing a substrate to one or more volatile precursors which react and/or decompose onto the substrate to produce a film. Most ALD processes are based on binary reaction sequences, where each of the two surface reactions occurs sequentially. Because the surface reactions are sequential, the two gas phase reactants are not in contact, and possible gas phase reactions that may form and deposit particles are limited. Current methods for depositing metal oxide films, particularly strontium oxide films involve the use of ozone which results in the formation of SrCO3, which is undesirable. Thus, there is a need to develop methods of depositing thin SrO films without the formation of SrCO3.